Patrick Rosch, engineering manager in the state Department of Environmental Quality's water quality division, said geography is the biggest factor in determining which water systems are struggling.
“The western part of Oklahoma has been much dryer,” Rosch said. “But the extreme drought conditions are pushing further and further east, so a lot of the systems in central Oklahoma are having it just as bad.”
The latest U.S. Drought Monitor report shows the entire state under at least moderate drought conditions.
The report has five conditions, from abnormally dry on the low end to exceptional drought on the high end. More than 42 percent of the state is listed in the exceptional drought category, mostly in the western part of Oklahoma.
The bulk of central Oklahoma falls in the second-highest extreme drought category, while the severe and moderate drought conditions prevail in eastern parts of the state.
Oklahoma City has called for mandatory odd-even watering restrictions this week. It's the first time in a decade the city has done so. Oklahoma City rarely needs to ration water because unlike many major cities in the region, elected leaders long ago secured ample water supplies.
Thirteen other metro communities also have to abide by Oklahoma City's water restrictions because they buy some or all of their water from Oklahoma City. Debbie Regan, spokeswoman for Oklahoma City's Utilities Department, said the mandatory rationing which went into effect Wednesday has decreased water use in the last couple of days.
“If we can continue and get everyone to participate in this program and just be mindful in the amount of water they are using, we expect to maintain the system as we have it now through the rest of the summer,” Ragan said.
The city's problem isn't supply. There is plenty of water in the city's lakes. The issue is the city's ability to treat enough water to maintain good water pressure in everyone's faucets. As people try harder and harder to keep their grass green in the face of scorching heat and no rain, more of that treated water ends up in sprinkler systems.
Ragan said the city doesn't expect to put more stringent rationing measures in place, even if the heat wave continues for the rest of the summer.
“I think we will see more and more people backing off and letting the Bermuda grass go,” Ragan said. “It's water they pay for. I know several people who have already given up.”